Magnetic ball switch for electric circuits



E. J. Dl NolA 3,103,562

MAGNETIC BALL .SWITCH FOR ELECTRIC CIRCUITS I sept.- 1o, 1963 5Sheets-Sheet l Filed July 50, 1959 INVENTOR. EMANUEL J. DI Nom ATTORNEYSept. 10, 1963 E. J. Dl NolA 3,103,562

MAGNETIC BALL swITCH ECR ELECTRIC CIRCUITS Filed July so, 1959 5sheets-sheet 2 /IIIIUIIIIIINN E 4@ 1N V EN TOR.

EMQNUEL J` D: Nom

HTTOENEY Sept. 10, 1963 E. J. DI NolA MAGNETIC BALL swITCH TOR ELECTRICCIRCUITS 5 Sheets-Sheet 3 Filed July 50, 1959 INVENTOR. EMANUEL J` DINom @WLM HTTOPNET Sept. 10, 1963 E. J. DI NOlA MAGNETIC BALL SWITCH FORELECTRIC CIRCUITS Filed July 50, 1959 IIHIIIIIHHIIIIIIHIIHIIIIHIIIHIIIHII III! IIII |IIl||IIIIIIIIIIIIIIIIIIIHIIIIIIIIHIIIIHHII IHIIIIIII 5 Sheets-Sheet 4 INVENTOR. EMANUEL J. DI Nom BY@Vy/TIM HTTO EN EY Sept. 10, 1963 E. J. DI NOIA MAGNETIC BALL SWITCH FORELECTRIC CIRCUITS Filed July so, 1959 TELTIE.

5 Sheets-Sheet 5 u u J U ---e5/ 92 6o% ^--55% Qqv: f --5o% --QOZJNVENToR. EMQNUEL J DI Nom QTTO ENE Y TcllZ.

'bilization within Wide temperature ranges. material of thesecharacteristics may be used. The mag- `in FIGS. 2 and 3, it will beunderstood that this assembly may be repeated :at spaced elevations in acontainer to indicate the level at corresponding intervals in the`height of the container.

their magnetism rand the ball slug immediately rbreaks away from theterminals.

The permanent magnet is of Indox, a material having Ia high energyproduct, high coercive force and good sta- Any other net need not becircular las bar magnets, horse shoe mag- Vnets, and magnets of othershapes maybe used. However, ring magnets of the sintered ceramic typeare used.

- The contact terminals and ball slug may be plated with The enclosingtubes of dielectric rnlaterial may of glass, quartz, lavite `epoxyresin, vTeilen or Kel-'F materials.

yIn FIGS. 4-7 an arrangement of switches of my invenk tio-n forindicating the position of a reactor rod is shown.

In this arrangement a series of switches is placedin spaced,longitudinal sequence in 1an enclosin g tube in such rnanner that theybridge an-d close an electric circuit trom a common lead to` severalleads leading from the successive switches` to a suitablerindicatingdevice. The

switches Iare closed rand Iopened in successive sequence by the magneticiieldy of a permanent magnet carried on a reactor rod movable lengthwiseof the series of switches. Accordingly when the reactor rod is in anyposition its magnet closes .a corresponding switch. The successivecircuits closed in this manner actuate the position indicator through aresistance system or other known actuating device. l i

v Referring to FIG. 5, each ofra succession of ball slugs 41 is movablein a channel 42 of its switch housing 43 of non-conductive or dielectricmaterial from the position shown in full lines to that shown in brokenlines.

vIn the latter position it *bridges la pair of spaced contacts ventionand is thereto-re not illustrated. It may be any suitable electricallyoperated device as, for example, one

Ain which the lead 46 is grounded and the individual leads 47 areconnected between resistances in series to control an indicator`operating current or voltage.

rllhe conta-cts `44 and 4S lare separated by a separator 48 ofinsulating material, 'which may lbe an extension of the housing 43 of anadjacent switch. |The hou-.sings 43 are enclosed in a tube 49 which iisslit at 50 and 51, FIGS. 6 and 7, on diametrically opposite sides topermit projections 52 of the contacts 44 and 45 to extend therethroughfor connection to the leads 46 and 47. The lead 46 vextendslongitudinally of the tube in the slot on one side of the tube and isthreaded through beads 53' of glass or other insulating ntaterial. Awasher 54 of dielectric niaterial is placed between successive housings43, being centered by la round projection 55 of one housing extendinginto :a hole of the washer and havin-g projecting ears 56 to receive theleads 46 and 47. vThe leads 47 are insulated by a jacket of insulatingmaterial which.4 lfor use lat elevated temperatures, may be of Teilon.

The tube y49 is enclosed in a thirnble 57, closed at its `.freeend bya'plug 58 recessed to receive one end of the tube 49.r It is spacedaxially inthe thirnble by theplug l 58 and at intervals in its length byspacers 59 which may characters as in FIGS. 4-7.

also serve to hold the leads 46 and 47 in position. 'Ilhe other end ofthe tube is held in a nut 60 which turns freely on the tube and isthreaded in threads 61 in the thimblle to enable the position of -thetube to be adjusted in its axial position relative to the thimble. Thenut 60 may be locked in its adjusted position byk means ott a lock nut62. The leads pass through a plate 63 spanning the end off the thimbleopposite the plug 58. This end oi the thimble may be threaded externallyfor mounting on a xed part of the reactor structure. rIlhe tube, thimbleand spacers 59 are of non magnetic material.

The ball plugs 41 are moved to and from the contacts 44 and l45 by amagnetic field generated by a magnetized ning 64 encircling and slidablelongitudinally of the thimble. The ring is carried by rods 65 movable'longi- 'tudinally of the thimble by a moving part of the reactorapparatus. `As'the ring moves in one direction ory the other itsmagnetic field moves successive ball slugs to or from the contacts,thusputting into or removing successive resistances.l v FIGS. 8 to l1show lan arrangement similar to that of FIGS. 4 to 7 except thatresistances for the several switches lare incorporated in the tube.elements are therefore identified with the same reference In themodification shown in FIGS. 8 and 1'0, the successive switch housings`43` are separated and spacedby resistor housings 66, eachucontaining aresistor l67. An

insulated lead wire 68 extends fromeach resistor to the next 4and lisalso electrically Vconnected to `the projection 52 of each contact 45 toconnect these contacts in series. As the ball slug 41 of each switch ismoved by the magnetic field .into contact with ther contacts l44 and 45it closes a circuitv between the wires 46 and 68 and short oircuitstheresistors farther Ifror'n' the fixed end of tem is similar to that ofFIGS. 8 land 10 except that,

instead orf the wires 68 extending into the housings 66,

they are connected to electrically conductive plates 69,

one at each' end or the housings 43 and electrically connected to 'theends of resistance coils 70 wound on insulating spacers` 71y extendingfrom one housing Ito the next.

The magneticiield may be such that combinations of two successiveswitclhes can be closed simultaneously so that a continuous steppingindication is provided, For

example, switches 1 and 2'c1ose simultaneously, then `2y and 3', then 3and 4 and so on. Tlhe arrangement of the switches foruse with a float 1sshown in FIGS. l2 and 13. In this arrangement the d Yswitch `apparatusis mounted in the top of a tank which,

as shown in the drawings, is a horizontal, cylindrical, tank and extendsvertically downwardly to nearly the bottorn. ,The tank is provided. witha mounting plug 72 threaded in an opening in rthe top of the tank sothat it may be removed. The plug has a central hole 73 provlded with alower threaded part y74 of vlesser diameter into which is threaded aplug 75 having a projection 76 to which is secured the upper end of atube 77 similar .tothe switch carrying `tube described above. -Byscrewing the' 'plug upwardly or downwardly, the position of the tube maybe adjusted vertically. The tube is` slit'on diametrically oppositesides and its lower end is closed.

y. A numberfof ball slug housings 78 are mounted in the tube, thelowermost resting on the bottom of the tube and each being provided witha pair of spaced contacts` 79 and 'S0 andwith each of the housings,excepting thev v bottom one, restingon the contacts olf the housing justbeneath it; These housings are of non magnetic, insulating', material-Each pair of contacts may be held spaced by a tongue 81 of the nexthigher housing extending into the space between thecontacts.The'housiingsare held vin.closelypacked contact by a screw plug 82.threaded in a vertical, fthreaded,'hole 86 in the mounting plug TZCorresponding pressing downwardly on a pressure plug 84 which bears i onthe uppermost housing.

Each housing has a chamber 85 in which is a ball slug 86 of magneticmaterial movable vertically upwardly by an upwardly movable magneticiield to bridge the contacts 79 and 80. I'he contacts 79 are connectedin series to a common lead `87 while each of the contacts 80' isconnected to an individual lead 88. These several leads extend toresistances not shown, outside the tank which control electric energychanges which actuate an indicating means.

The tube 77 is enclosed co-axially in a thimble 819 secured at its upperend to the mounting plug 72 and closed at its lower end by a plug 90having a central recess -91 in wlhicli Ithe lower end of the tube isguided in its vertical adjustment.

The thimble 89 is co-axially enclosed in a cylinder 92 secured at itsupper end to the mounting plug 72 and having a bottom Wall with arecessed, upwardly extending boss 93 in which the plug 90' ispositioned. 'Ilhe wall of the cylinder 92 .is provided with a series offvertically spaced groups of openings 94' through which liquid may flowinto and out of a space 95 between the thimble and the imite-riorsurface of the cylinder.

A11 annular float 96 in the space 95- and encircling the thimble t89nises and falls with the rise and fall of the liquid level in the space915 and carries an annular magnetized ring 97 which creates a magneticfield through the walls of the thimble and tube, which are ofnonmlagne-tic material, to move the ball slugs of successively higherlevel into bridging contact with their contacts as the level of theliquid rises and conversely carries ball slugs of successively lowerlevel into contact as the liquid level falls.

The outer surface orf the cylinder carries level indicating marks 918lto which the contacts 719l and 80 are made to match by an adjustment ofthe tube 77.

Through the above combination, the level in the tank may be indicatedaccurately by an indicator system mechanism outsidev the tank. inasmuchas the contacts are enclosed within the thimb'le lthey are separatedfrom the liquid and from any combustible vapors in case the liquidV inthe tank evolves combustible vapors. Tlhe magnetized ring 97 cannotcause any sparking.

` Having described my invention, I claim:

1. A switch circuit for indicating the position of a movable mass whichcomprises a thimble of non-magnetic material having one end closed andthe opposite end tted for attachment to a support, the closed end ofsaid thimble having an axially extending guide surface; a tube mountedco-axially in said thimble and being slidably guided by said guidesurface for adjustment longitudinally in said fthimble, said tube beingof lesser diameter than said thimble to provide an annular space; meansat the end opposite 4said guided surace to support said tube inpositions of longitudinal adjustment; a series of electric 6 switchesin, and spaced longitudinally of, said tube, each said switch comprisinga housing having a longitudinally extending chamber, a pair of spacedcontacts at one end of said chamber, and a magnetic ball slug movable insaid chamber to bridge said contacts; an electric circuit havingconnections to said contacts to close short circuits therethrough; amagnetized ring in said annular space movable longitudinally of saidtube and encircling said tube to provide a longitudinally movablemagnetic fieldk therein to move said ball slugs to and from saidcontacts.

2. The switch circuit of claim 1 having a lead connecting one of eachpair of contacts in series and separate leads connected to the othercontacts of each pair of contacts.

3. The switch circuit of claim l having insulating spacers between thecontacts of each pair.

4. The switch circuit of claim 1 hav-ing a rod movable longitudinally ofsaid tube and attached to said magnetized ring to move said ringlongitudinally of said tube.

5. The switch circuit of claim 1 having resistances l positioned betweensaid switches, a lead connecting one contact of each switch in serieswith the others and leads connecting each of the other contacts with theresistances positioned betweenV said switches.

6. The switch circuitof claim 5 in which said resisrtances are enclosedin insulating housings.

7. The switch circuit of claim 5 in which each resistance comprises aspacer of insulating material and a resistance coil wound on saidspacer.

8. The switch circuit of claim l having a cylinder enclosing andco-axial with said thimble and forming an annular space about saidthimble, said cylinder having openings to admit liquid into said annularspace through said openings.

9. The switch circuit of claim 8 having means to adjust said tubelongitudinally of said cylinder.

References Cited in the le of this patent UNITED STATES PATENTS GreatBritain Apr. 9,

1. A SWITCH CIRCUIT FOR INDICATING THE POSITION OF A MOVABLE MASS WHICHCOMPRISES A THIMBLE OF NON-MAGNETIC MATERIAL HAVING ONE END CLOSED ANDTHE OPPOSITE END FITTED FOR ATTACHMENT TO A SUPPORT, THE CLOSED END OFSAID THIMBLE HAVING AN AXIALLY EXTENDING GUIDE SURFACE; A TUBE MOUNTEDCO-AXIALLY IN SAID THIMBLE AND BEING SLIDABLY GUIDED BY SAID GUIDESURFACE FOR ADJUSTMENT LONGITUDINALLY IN SAID THIMBLE, SAID TUBE BEINGOF LESSER DIAMETER THAN SAID THIMBLE TO PROVIDE AN ANNULAR SPACE; MEANSAT THE END OPPOSITE SAID GUIDED SURFACE TO SUPPORT SAID TUBE INPOSITIONS OF LONGITUDINAL ADJUSTMENT; A SERIES OF ELECTRIC SWITCHES IN,AND SPACED LONGITUDINALLY OF, SAID TUBE, EACH SAID SWITCH COMPRISING AHOUSING HAVING A LONGITUDINALLY EXTENDING CHAMBER, A PAIR OF SPACEDCONTACTS AT ONE END OF SAID CHAMBER, AND A MAGNETIC BALL SLUG MOVABLE INSAID CHAMBER TO BRIDGE SAID CONTACTS; AN ELECTRIC CIRCUIT HAVINGCONNECTIONS TO SAID CONTACTS TO CLOSE SHORT CIRCUITS THERETHROUGH; AMAGNETIZED RING IN SAID ANNULAR SPACE MOVABLE LONGITUDINALLY OF SAIDTUBE AND ENCIRCLING SAID